PIRATE 14 
A. —Tulip tree (Liriodendron tulipifera), transplanted in April and placed out of 
doors. On September 8 the tree was transferred to the greenhouse. There was the 
usual loss of leaves by abscission, followed by dormancy which continued through 
the winter. Photographed November 18. 
B. —Tulip trees, treated in all particulars like the individual shown in A except 
that after transfer to the greenhouse the trees received electric illumination from 
sunset till midnight, in addition to the natural daylight. Under these conditions, 
the rest period was eliminated. Growth was promptly renewed and continued 
throughout the winter. A characteristic feature was failure to form the absciss layer 
when old leaves died here and there on the trees. These dead leaves remained firmly 
attached to the stem, in marked contrast with the usual behavior of this species. 
Photographed November 18. 
